Artificial intelligence (AI for short) is a new technical science studying and developing theories, methods, techniques and application systems for simulating, extending and expanding human intelligence. The artificial intelligence is a branch of computer science, which attempts to know the essence of intelligence and to produce a new intelligent machine capable of acting in a same way as human intelligence. The researches in this field include robots, speech recognition, image recognition, natural language processing and expert systems, etc.
In speech signal processing, the higher the sample frequency of a digital speech signal is, the more the information contained in the digital speech signal is, and the better the quality of the speech is. Therefore, in technologies such as speech recognition, speech synthesis and the like, a speech having a high sample frequency has obvious performance advantages to a speech having a low sample frequency.
However, in a practical sampling process, the higher the sample frequency is, the higher the requirements for a processing speed and storage of a digital signal processing system are. Therefore, a modest sample frequency is selected to perform sampling on simulation speech signals. This requires to perform up-sampling on a speech signal with a low sample frequency.
In the related art, digital signal processing is usually used to improve the sample frequency of a speech, in which, by inserting a fixed value between sampling points, the number of sampling points in unit time is improved, and then filtering is performed by a low pass filter. However, by the above modes, the fixed value is forcibly inserted between sampling points. This causes that change in speech information is little, generated speech information is insufficient, moreover, the low pass filter may lead to a loss of original information of a speech to some extent. Therefore, quality of obtained speech signal is low, and user experience is poor.